feat: finish challenge

packages/hardhat/contracts/Vendor.sol

@@ -10,18 +10,26 @@ contract Vendor is Ownable {
     /////////////////
 
     // Errors go here...
+    error InvalidEthAmount();
+    error InsufficientVendorTokenBalance(uint256 available, uint256 required);
+    error EthTransferFailed(address to, uint256 amount);
+    error InvalidTokenAmount();
+    error InsufficientVendorEthBalance(uint256 available, uint256 required);
 
     //////////////////////
     /// State Variables //
     //////////////////////
 
     YourToken public immutable yourToken;
+    uint256 public constant tokensPerEth = 100;
 
     ////////////////
     /// Events /////
     ////////////////
 
     // Events go here...
+    event BuyTokens(address indexed buyer, uint256 amountOfETH, uint256 amountOfTokens);
+    event SellTokens(address indexed seller, uint256 amountOfTokens, uint256 amountOfETH);
 
     ///////////////////
     /// Constructor ///
@@ -35,9 +43,29 @@ contract Vendor is Ownable {
     /// Functions /////
     ///////////////////
 
-    function buyTokens() external payable {}
+    function buyTokens() external payable {
+      if (msg.value == 0) revert InvalidEthAmount();
+      uint256 receivedToken = msg.value * tokensPerEth;
+      uint256 availableToken = yourToken.balanceOf(address(this));
+      if (availableToken < receivedToken) revert InsufficientVendorTokenBalance(availableToken, receivedToken);
+      yourToken.transfer(msg.sender, receivedToken);
+      emit BuyTokens(msg.sender, msg.value, receivedToken);
+    }
 
-    function withdraw() public onlyOwner {}
+    function withdraw() public onlyOwner {
+      address ownerAddr = payable(owner());
+      (bool sent,) = ownerAddr.call{value: address(this).balance}("");     
+      if (!sent) revert EthTransferFailed(ownerAddr, address(this).balance);
+    }
 
-    function sellTokens(uint256 amount) public {}
+    function sellTokens(uint256 amount) public {
+      if (amount == 0) revert InvalidTokenAmount();
+      yourToken.transferFrom(msg.sender, address(this), amount);
+      uint256 receivedEth = amount / tokensPerEth;
+      uint256 contractEth = address(this).balance;
+      if (contractEth < receivedEth) revert InsufficientVendorEthBalance(contractEth, receivedEth);
+      (bool sent,) = payable(msg.sender).call{value: receivedEth}("");
+      if (!sent) revert EthTransferFailed(msg.sender, receivedEth);
+      emit SellTokens(msg.sender, amount, receivedEth);
+    }
 }

packages/hardhat/contracts/YourToken.sol

@@ -6,5 +6,7 @@ import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
 // learn more: https://docs.openzeppelin.com/contracts/5.x/erc20
 
 contract YourToken is ERC20 {
-    constructor() ERC20("Gold", "GLD") {}
+    constructor() ERC20("Gold", "GLD") {
+      _mint(msg.sender, 1000 * (10 ** 18));
+    }
 }

packages/hardhat/deploy/01_deploy_vendor.ts

@@ -27,14 +27,14 @@ const deployVendor: DeployFunction = async function (hre: HardhatRuntimeEnvironm
    * Student TODO:
    * - Put the address you’re using in the frontend here (leave "" to default to the deployer)
    */
-  const FRONTEND_ADDRESS: string = "";
+  const FRONTEND_ADDRESS: string = "0x253F67DF832aBADb8A54aAA9b4A2635fbeDa4Ccf";
 
   /**
    * Mode switch:
    * - If true: deploy Vendor and seed it with the token balance
    * - If false: send tokens to your frontend address (or deployer if unset)
    */
-  const SEND_TOKENS_TO_VENDOR = false; // Don't switch until Checkpoint 2!
+  const SEND_TOKENS_TO_VENDOR = true; // Don't switch until Checkpoint 2!
 
   const recipientAddress = FRONTEND_ADDRESS && FRONTEND_ADDRESS.trim().length > 0 ? FRONTEND_ADDRESS : deployer;
 

packages/hardhat/deployments/sepolia/.chainId

@@ -0,0 +1 @@
+11155111

packages/hardhat/hardhat.config.ts

@@ -37,7 +37,7 @@ const config: HardhatUserConfig = {
       },
     ],
   },
-  defaultNetwork: "localhost",
+  defaultNetwork: "sepolia", //"localhost",
   namedAccounts: {
     deployer: {
       // By default, it will take the first Hardhat account as the deployer

packages/nextjs/app/events/page.tsx

@@ -12,11 +12,11 @@ const Events: NextPage = () => {
     eventName: "BuyTokens",
   });
 
-  // // SellTokens Events
+  // SellTokens Events
-  // const { data: sellTokenEvents, isLoading: isSellEventsLoading } = useScaffoldEventHistory({
+  const { data: sellTokenEvents, isLoading: isSellEventsLoading } = useScaffoldEventHistory({
-  //   contractName: "Vendor",
+    contractName: "Vendor",
-  //   eventName: "SellTokens",
+    eventName: "SellTokens",
-  // });
+  });
 
   return (
     <div className="flex items-center flex-col flex-grow pt-10">
@@ -66,7 +66,7 @@ const Events: NextPage = () => {
       </div>
 
       {/* SellTokens Events */}
-      {/* <div className="mt-14">
+      <div className="mt-14">
         <div className="text-center mb-4">
           <span className="block text-2xl font-bold">Sell Token Events</span>
         </div>
@@ -108,7 +108,7 @@ const Events: NextPage = () => {
             </table>
           </div>
         )}
-      </div> */}
+      </div>
     </div>
   );
 };

packages/nextjs/app/token-vendor/page.tsx

@@ -33,18 +33,18 @@ const TokenVendor: NextPage = () => {
   const { writeContractAsync: writeVendorAsync } = useScaffoldWriteContract({ contractName: "Vendor" });
   const { writeContractAsync: writeYourTokenAsync } = useScaffoldWriteContract({ contractName: "YourToken" });
 
-  // const { data: vendorTokenBalance } = useScaffoldReadContract({
+  const { data: vendorTokenBalance } = useScaffoldReadContract({
-  //   contractName: "YourToken",
+    contractName: "YourToken",
-  //   functionName: "balanceOf",
+    functionName: "balanceOf",
-  //   args: [vendorContractData?.address],
+    args: [vendorContractData?.address],
-  // });
+  });
 
-  // const { data: vendorEthBalance } = useWatchBalance({ address: vendorContractData?.address });
+  const { data: vendorEthBalance } = useWatchBalance({ address: vendorContractData?.address });
 
-  // const { data: tokensPerEth } = useScaffoldReadContract({
+  const { data: tokensPerEth } = useScaffoldReadContract({
-  //   contractName: "Vendor",
+    contractName: "Vendor",
-  //   functionName: "tokensPerEth",
+    functionName: "tokensPerEth",
-  // });
+  });
 
   return (
     <>
@@ -57,8 +57,7 @@ const TokenVendor: NextPage = () => {
               <span className="font-bold ml-1">{yourTokenSymbol}</span>
             </div>
           </div>
-          {/* Vendor Balances */}
+          <hr className="w-full border-secondary my-3" />
-          {/* <hr className="w-full border-secondary my-3" />
           <div>
             Vendor token balance:{" "}
             <div className="inline-flex items-center justify-center">
@@ -69,11 +68,10 @@ const TokenVendor: NextPage = () => {
           <div>
             Vendor eth balance: {Number(formatEther(vendorEthBalance?.value || 0n)).toFixed(4)}
             <span className="font-bold ml-1">ETH</span>
-          </div> */}
+          </div>
         </div>
 
-        {/* Buy Tokens */}
+        <div className="flex flex-col items-center space-y-4 bg-base-100 shadow-lg shadow-secondary border-8 border-secondary rounded-xl p-6 mt-8 w-full max-w-lg">
-        {/* <div className="flex flex-col items-center space-y-4 bg-base-100 shadow-lg shadow-secondary border-8 border-secondary rounded-xl p-6 mt-8 w-full max-w-lg">
           <div className="text-xl">Buy tokens</div>
           <div>{tokensPerEth?.toString() || 0} tokens per ETH</div>
 
@@ -98,7 +96,7 @@ const TokenVendor: NextPage = () => {
           >
             Buy Tokens
           </button>
-        </div> */}
+        </div>
 
         {!!yourTokenBalance && (
           <div className="flex flex-col items-center space-y-4 bg-base-100 shadow-lg shadow-secondary border-8 border-secondary rounded-xl p-6 mt-8 w-full max-w-lg">
@@ -132,7 +130,7 @@ const TokenVendor: NextPage = () => {
         )}
 
         {/* Sell Tokens */}
-        {/* {!!yourTokenBalance && (
+        {!!yourTokenBalance && (
           <div className="flex flex-col items-center space-y-4 bg-base-100 shadow-lg shadow-secondary border-8 border-secondary rounded-xl p-6 mt-8 w-full max-w-lg">
             <div className="text-xl">Sell tokens</div>
             <div>{tokensPerEth?.toString() || 0} tokens per ETH</div>
@@ -180,7 +178,7 @@ const TokenVendor: NextPage = () => {
               </button>
             </div>
           </div>
-        )} */}
+        )}
       </div>
     </>
   );

packages/nextjs/next-env.d.ts

@@ -1,6 +1,5 @@
 /// <reference types="next" />
 /// <reference types="next/image-types/global" />
-/// <reference path="./.next/types/routes.d.ts" />
 
 // NOTE: This file should not be edited
 // see https://nextjs.org/docs/app/api-reference/config/typescript for more information.

packages/nextjs/scaffold.config.ts

@@ -15,7 +15,7 @@ export const DEFAULT_ALCHEMY_API_KEY = "cR4WnXePioePZ5fFrnSiR";
 
 const scaffoldConfig = {
   // The networks on which your DApp is live
-  targetNetworks: [chains.hardhat],
+  targetNetworks: [chains.sepolia], //[chains.hardhat],
   // The interval at which your front-end polls the RPC servers for new data (it has no effect if you only target the local network (default is 4000))
   pollingInterval: 30000,
   // This is ours Alchemy's default API key.
@@ -34,7 +34,7 @@ const scaffoldConfig = {
   // It's recommended to store it in an env variable:
   // .env.local for local testing, and in the Vercel/system env config for live apps.
   walletConnectProjectId: process.env.NEXT_PUBLIC_WALLET_CONNECT_PROJECT_ID || "3a8170812b534d0ff9d794f19a901d64",
-  onlyLocalBurnerWallet: true,
+  onlyLocalBurnerWallet: false,
 } as const satisfies ScaffoldConfig;
 
 export default scaffoldConfig;